Improvement in endless-chain propellers



' 4 Sheets-Sheet 1.

H. EXALL.

Endless-Chain Propeller.

No. 206,551. Patented July 30,1878

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4 SheetsSheet 2.

v H. EXALL Endless-Chain Propeller.

No. 206,551. Patented July 30,1878.

ATTORNEYS.

I 4 Sheets-Sheet 3. H. EXALL.

Endless-Chain Hopeller. No. 206,551. Ptented July 30,1878.

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4 Sheets-Sheen 4.

H. EXALL. Endless-Chain Propeller.

No. 206,551. Patented July 30,1878.

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HENRY EXALL, OF RICHMOND, VIRGINIA.

IMPROVEMENT IN ENDLESS-CHAIN PROPELLERS.

Specification forming part of Letters Patent No. 206,551 dated July 30,1878 application filed June 13, 1878.

To all whom it may concern:

Be it known that I, HENRY EXALL, of Richmond, in the county of Henricoand State of Virginia, have invented a new and Improved Endless-ChainPropeller; and I do hereby declare that the following is a full, clear,and exact description of the same, reference being had to theaccompanying drawing, forming part of this specification, in whichFigure l is a vertical longitudinal section of the forward, and Fig. 2the same view of the aft, part of a boat to which my invention is shownapplied. Fig. 3 is a plan view of the forward, and Fig. 4. the same viewof the aft, part of the boat, the deck being removed; Fig. 5, a verticaltransverse section on an e11- larged scale. Figs. 6, 7,8,9 are enlargeddetail views of the propeller-chain coupling, showing also the relationof the grabs of the wheels. Fig. 10 is an enlarged detail view of one ofthe paddles.

My invention relates to an improved endlesschain propeller constructedwith a view to avoiding the objections incident to the use of thescrew-propeller, and yet free from the complex and impracticable plansof the endlesschain propeller as heretofore attempted.

The defects of the screw-propeller for speed are due to the greatdisproportion of its resisting-surface to the resisting-surface of thevessel which it is designed to move, and with this form of propelleronly a limited degree of speed can be obtained, for, after a certainrapidity of revolution has been obtained, any further increase has nocorresponding eifect in increasing the speed of the boat, but onlyproduces foaming of the; water. 7 Its location at the stern alsoproduces racing or sudden speeding of the propeller when the stern ofthe vessel is lifted out of the water by heavy swells, which frequentlyinvolves the breakage of the shaft and other derangement, to say nothingof the loss of effect upon the boat.

In adopting the endless-chain form of propeller I have taken advantageof conditions which obviate the objection just mentioned, and whichsecure an anchorage in the water, whereby the boat is more positivelypropelled, in contradistinction to producing currents in the water, andthus securing only a partial effect of the motive-power expended.

My invention consists, chiefl y, in the form of the endless-chain, ofwhich I employ two, one on each side of the boat, and the generalarrangement of the chains and wheels with respect to the boat, designedto secure economy of space, a large operating-surface for the paddles,and compactness and strength of structure.

The invention also consists, among other details, in utilizing the draftof air produced by the return of the chain-paddles in the chainbox forthe purpose of ventilating the boat and supplying the same with freshair, as

hereinafter more fully described.

In the drawing, A represents the hull of the boat, which may beconstructed after anysuitable model, the form here shown being that of acanal-boat, to which my invention may be applied to advantage.Longitudinal] y with the boat, and upon each side of the keel, areformed independent channels or ways B, Figs. 1, 2, 5, to receive thechain-paddles, which channels open laterally'into' the water, and arefurther deepened byprotect-ivekeels O C, Fig. 5, which extend below thebottom of the chainpaddles and protect them against breakage fromobstructions. Near the forward and aft portions of the boat, in suitableand substantial bearings, are arranged the transverse shafts I) 1) ofthe two chain-wheels E E. About these wheels are formed wells F F, ornarrow compartments to receive the wheels, which wells open through thebottom of the boat into the water, and are widened at the periphery ofthe wheels, where the chain touches them, to accommodate the passage ofthe paddles of theendless chain. G are said endless chains, which passaround both the wheels, and, descending through the wells, enter andmove in the channels B beneath the boat and between the heels, to form,by their great superficial area, a decided anchorage in the water,against which the strain of the motive power is directed to give a morepositive movement to the boat.

In constructing the chain-propeller I employ stiff sheet-metal disks(1., which disks are rigidly attached to the middle portions oflooselyjointed rods 1). In connecting these rods into a flexiblecontinuous chain each rod terminates at its extremities with detachablescrew-nuts c, Fig. 9, which are rounded upon one side and secured in ahollow circulan shaped shell, d, to form a sort of double balland-socketjoint. In connecting these rods with the shell the rods are insertedendwise through holes in the ends of the shells, the nuts insertedlaterally through a middle hole in the shell, and then screwed upon theends of the rods. This makes a detachable coupling, and at the same timea very strong and secure one. In addition to the function of connectingthe rods, these shells d form projections on the chain, which are seizedby the grabs or seats h of the chain-wheel, as shown in Figs. 6 and 7,thus permitting the latter to secure a firm hold upon the chain midwaybetween the disks. The wheels E, Figs. 1, 2, 5, are constructed withhubs c, tubular spokes f, and bracing circular rims g, the said spokeshaving at their extremities forks, seats, cups, or grabs h, Figs. 6 and7, which are adapted to receive the shells (Z of the chain.

In imparting motion to the wheels, and through them to the chains, anyform of engine with suitable connections may be employed. As shown, adouble oscillating engine, H, Figs. l and 5, is made to operate throughthe crank-plate I upon the shaft J, which latter carries a pinion, K,engaging with a large spurwheel, L, fixed upon the rear one of theshafts D D, which connect the two sets of wheels.

N N, Figs. 1, 2, and 5, are the chain-boxes, which extend from theforward to the aft wheels, and inclose the portion of the chains andattached paddles extending from the tops of the front and rear wheels.These boxes project above the upper deck and serve as seats 3 and as therear movement of the paddledisks in these boxes produces a decidedcurrent of air, their closed character permit them to be used forventilating-the various portions of the boat and supplying fresh andpure air to the different parts of the same. As the paddles enter theseboxes at the rear and pass to the front, air is carried in with them,and a forwardly-moving current produced. All that is necessary then toutilize the same is to keep the front-wheel compartment closed and carrythe draft by means of pipes to the point desired, the air being alwaysfresh, pure, and cool from its contact with the wetted surfaces.

The distinctive advantages of my invention are as follows: First, themanner of connectin g the rod-sections to form a chain not only securesgreat strength and durability, but the coupling-shell affords a purchasefor the grabs or forks of the wheel; secondly, the location of the rigiddisk blades or paddles midway upon the rod-section and centrally uponthe same simplifies the form of chain propeller and reduces liability toderangement; thirdly, the small transverse dimension of the wheels andchain-propellers enables me to economize space and to utilize the vacantspace even between the two wheels on the same shaft, whlch hasheretofore been lost.

Having thus described my invention, what I claim as new is- 1. Theendless-chain propeller consisting of jointed rod-sections having diskblades or paddles rigidly secured at their centers to the rodsectionsand between the joints of the same, substantially as described.

2. The endless chain consisting of rod-sections having terminal nuts,knobs, or heads, combined with an inclosing-shell adapted to couple therod-sections and form a hold for the grabs of the wheel, as set forth.

3. The combination, with the chain-propeller Gr, consisting of jointedrod-sections, couplingof the wheels in contact with the chain, as

shown and described.

6. In a boat propelled by an endless-chain propeller, the method ofventilating the same by means of a current of air produced in a closedreturn-chain box, provided with suit- ?ble ventilating-pipes,substantially as set orth.

HENRY EXALL.

Witnesses:

v SoLoN O. KEMON, OHAs. A. PETTIT.

